<template lang="html">
    <div class="xtx-numbox">
        <div class="label">数量</div>
        <div class="numbox">
            <a @click="changeNum(-1)" href="javascript:;">-</a>
            <input type="text" value="1" readonly>
            <a @click="changeNum(1)" href="javascript:;">+</a>
        </div>
    </div>
</template>
<script>
import { useVModel } from '@vueuse/core';
export default {
    name:'XtxNumBox',
    props:{
        label:{
            type:String,
        },
        modelValue:{
            type:Number,
            default:1
        },
        min:{
            type:Number,
            default:1
        },
        max:{
            type:Number,
            default:100
        }
    },
    emits:['change'],
    setup(props,{emit}) {
      // 包装modelValue数据为num，num发生改变时触发emit，并把新值作为参数传给父组件
      // 此时的num就是父组件的响应式num
        const num = useVModel(props, 'modelValue', emit)
        const changeNum = (value) => {
            const newVal = num.value + value
            // 判断是否小于最小值
            if(newVal < props.min) return
            // 判断是否大于最大值 
            if(newVal > props.max) return
            num.value = newVal
            // newVal直接赋值给父组件的num
            emit('change', newVal)
        }

        return {
            num,
            changeNum
        }
    }
}
</script>
<style lang="less" scoped>
.xtx-numbox {
  display: flex;
  align-items: center;
  .label {
    width: 60px;
    color: #999;
    padding-left: 10px;
  }
  .numbox {
    width: 120px;
    height: 30px;
    border: 1px solid #e4e4e4;
    display: flex;
    > a {
      width: 29px;
      line-height: 28px;
      text-align: center;
      background: #f8f8f8;
      font-size: 16px;
      color: #666;
      &:first-of-type {
        border-right:1px solid #e4e4e4;
      }
      &:last-of-type {
        border-left:1px solid #e4e4e4;
      }
    }
    > input {
      width: 60px;
      padding: 0 5px;
      text-align: center;
      color: #666;
    }
  }
}
</style>